Rizk DV, et al. - In this prospective, open-label study, researchers developed and assessed a new rapid technique, the visible fluorescent injectate (VFI), for determining plasma volume and measurement of GFR (mGFR). VFI is a new exogenous biomarker and consists of a large 150-kD rhodamine derivative and small 5-kD fluorescein carboxymethylated dextrans. Assessment of plasma pharmacokinetics of the rhodamine derivative and fluorescein carboxymethylated dextrans can determine plasma volume and mGFR, respectively, following a single intravenous injection of VFI. VFI-based mGFR values were compared with values obtained by measuring iohexol plasma disappearance in adults with normal kidney function vs those with CKD. With the VFI-based approach, rapid determination of mGFR at the bedside was achieved with maintained patient safety, measurement accuracy and reproducibility.